Set includes two drill chuck keys, one designed for 10mm chucks and the other for 13mm chucks; ensurings that the keys can be used with a wide range of drills., Drill chuck keys are made from high-quality materials that ensure durability and longevity., Drill chuck keys are straightforward to use. Simply insert the key into the chuck's keyhole and rotate it clockwise or counterclockwise to tighten or loosen the chuck, respectively.